What to Do When the Thermostat Clicks but the AC Does Not Turn On

When you’re sitting near your thermostat in summer, you may hear a familiar click, indicating that the thermostat is sending a signal to your air conditioner that it is time to generate some cold air. But, what happens if your air conditioner doesn’t seem to turn on? Your house slowly gets hotter and your thermostat clicks to no end. There are a few things you can do to troubleshoot this issue before you reach out to the professionals.

Check the Relay

The thermostat’s click is the sound of a relay circuit being completed. This circuit is supposed to send a signal to the air conditioner to turn on. However, if it doesn’t get there, the air conditioner is never triggered. A single break in the relay lines that run to the air conditioner is enough to stop the proverbial baton from being passed on. You can check if the thermostat may have these problems by following these steps:

Look at the thermostat wiring: Are there any loose connections? Are there signs of damage?
Thermostat breaker: You can try to reset the thermostat by turning off its breaker in the home’s breaker box. Flip the breaker and wait for a minute or two. Then turn it back on. If the thermostat doesn’t recover after this, it is likely faulty.
Sounds: When you do flip the switch, have someone standing near the thermostat. Does the clicking sound louder than normal? Or does it click multiple times? Then it’s likely that the thermostat is the cause.

Capacitor Problems

When the thermostat isn’t the issue, then it must be something going on in the air conditioner itself. A one common problem is the capacitor. This is the part that, when the thermostat triggers it, gives the compressor an electrical charge to start it up. Unfortunately, the capacitor is not a simple or safe thing for a homeowner to check by themselves, as it controls electricity. We suggest you get professional help if you suspect your capacitor is the issue.

Control Board Issues

While capacitor troubles are likely, there are other potential problems within your air conditioner. One option is the control board. This is the electrical board that receives signals and send them out to different parts of the air conditioner, including the capacitor. You can check this one by listening to the air conditioner. If there is a clicking noise within it, that’s one sign the control board could be an issue.

Outdoor Unit

Another potential cause of your air conditioner woes is the contactor on the outdoor unit. This is the end of the relay from the thermostat to the outdoor unit. Again, you would hear a click at the outdoor unit if this was the issue.

Are You Sure the AC Is Off?

It sounds silly, but it happens to the best of us. You think the air conditioner isn’t turning on because you don’t feel cold air through the vents. But that could actually be because the air conditioner blower isn’t working. A professional can help you sort out what’s going on with your air conditioner or your thermostat when you find it isn’t working.